Buggy code:
public class DefaultAppDesign implements BrowserNavigationListener , IAppDesign { private static Log log = LogFactory . getLog ( DefaultAppDesign . class ) ; public static final String CSS_PREFIX = "atlas-panel" ; public static final String CSS_PANEL_HEADER = ( DefaultAppDesign . CSS_PREFIX ) + "-header" ; public static final String CSS_BREADCRUMP = ( DefaultAppDesign . CSS_PREFIX ) + "-breadcrump" ; public static final String CSS_SWITCHER = ( DefaultAppDesign . CSS_PREFIX ) + "-switcher" ; private DefaultAppManager appManager ; protected Display display ; protected Shell mainWindow ; protected BrowserNavigation browserHistory ; protected StatusManager2 statusManager ; protected DefaultUserPreferences userPrefs ; protected PageStack < PanelPath > panelsArea ; protected DefaultAppDesign . DefaultLayoutSupplier panelLayoutSettings = new DefaultAppDesign . DefaultLayoutSupplier ( ) ; protected DefaultAppDesign . DefaultLayoutSupplier appLayoutSettings = new DefaultAppDesign . DefaultLayoutSupplier ( ) ; @ Override public void init ( ) { } @ Override public void close ( ) { } @ Override public void navigated ( BrowserNavigationEvent ev ) { } @ Override public IPanelToolkit createToolkit ( PanelPath panelPath ) { } @ Override public Shell createMainWindow ( @ SuppressWarnings ( "hiding" ) Display display ) { } protected Composite fillHeaderArea ( Composite parent ) { } protected Composite fillPanelArea ( Composite parent ) { } @ Override public LayoutSupplier getAppLayoutSettings ( ) { } @ Override public LayoutSupplier getPanelLayoutPreferences ( ) { } protected void createPanelContents ( final IPanel panel , final Composite parent ) { } protected void createPanelDecoration ( IPanel panel , Composite head ) { } protected Button createSwitcherButton ( Composite switcher , IPanel panel ) { final Button btn = UIUtils . setVariant ( new Button ( switcher , SWT . PUSH ) , DefaultAppDesign . CSS_PANEL_HEADER ) ; btn . setLayoutData ( RowDataFactory . swtDefaults ( ) . hint ( DEFAULT , 21 ) . create ( ) ) ; boolean showText = ( UIUtils . sessionDisplay ( ) . getClientArea ( ) . width ) > 900 ; Image icon = panel . getSite ( ) . getIcon ( ) ; String title = panel . getSite ( ) . getTitle ( ) ; if ( ( icon == null ) && ( title == null ) ) { btn . setVisible ( false ) ; } else if ( showText || ( icon == null ) ) { <START_BUG> btn . setText ( ( title + "<seq2seq4repair_space>>" ) ) ; <END_BUG> } else { btn . setToolTipText ( title ) ; } if ( icon != null ) { btn . setImage ( icon ) ; } return btn ; } protected void updatePanelContents ( IPanel panel ) { } protected void updateMainWindowLayout ( ) { } @ EventHandler ( display = true ) protected void panelChanged ( PanelChangeEvent ev ) { } @ Override public void delayedRefresh ( ) { } public static class DefaultLayoutSupplier extends LayoutSupplier { public int marginLeft ; public int marginRight ; public int marginTop ; public int marginBottom ; public int spacing ; @ Override public int getMarginLeft ( ) { } @ Override public int getMarginRight ( ) { } @ Override public int getMarginTop ( ) { } @ Override public int getMarginBottom ( ) { } @ Override public int getSpacing ( ) { } } public static class DelegatingLayoutSupplier extends LayoutSupplier { private LayoutSupplier delegate ; public DelegatingLayoutSupplier ( LayoutSupplier delegate ) { } @ Override public int getMarginLeft ( ) { } @ Override public int getMarginRight ( ) { } @ Override public int getMarginTop ( ) { } @ Override public int getMarginBottom ( ) { } @ Override public int getSpacing ( ) { } } }

Fix:
btn . setText ( title ) ;